Ratio-adjusting switch



Dec. 16, 1930. 1 F. BLUME RATIO ADJUSTINGv SWITCH Filed Oct. 3, 1929 2 Sheets-Sheet Inventor, Louis lTBI urne .by H i s Att or-rw ey Filed Oct. 3, 1929 2 Sheets-Shes?l 2 Inventor-r Louis FIBlume? Patented ec. 16, 1930 UNITED STATES PATENT OFFICE LOUIS F. BLUME, OF PITTSFIELD, MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRC COMPANY, A CORPORATION OF YORK RATIO-ADJUSTING SWITCH Application iledk October 3, 1929. Serial No. 397,124.

My invention relates to switches. The general object of the invention is to provide a switch iaving main current carrying contacts with an improved arrangement of automatically controlled arcing contacts to prevent injury to the main contacts when the switch .is operated to open or close a circuit or to change circuit connections while the circuit is carrying current. The invention may be appiied with advantage and will be explained in connection with a switch of the type disclosed in Figures and 6 of my United Sta-tes Patent No. 1,535,807, issued April 28, 1925.

Other objects and advantages will be apparent from the following description taken in connection with the accompanying drawings in which Fig. 1 shows a switch, partly in section, made in accordance with the invention, and Figs. 2, 3 and 11 are sectional views on the lines 2-2, 3-3 and 1-4 respectively of Fig. 1.

Lilie reference characters indicate similar parts in the diderent figures of the drawings.

The particular switch shown in the drawn ings includes a plurality of spaced conducting rods or terminals 10, L11, 12, 13, 14 and 15 supported between a pair of insulating plates 16 and 1T and surrounding a central-shaft 18 carried in bearings in the plates 16 and 17. 1n Fig. 1, the terminal 15 is removed and other parts are shown in section to reveal the structure more clearly. Six of the terminals are shown spaced uniformly about the shaft 18 although it will be apparent that a larger or smaller number may be used if desired.

r1`he desired connections between the terminals are made by a connector 19 rotatably supported about an offset portion ofthe shaft 18 and including movable contacts 20 and 21 which are secured to the body of the connector 19 by springs 22.

The connector 19 is provi-ded with a rigid armr23 with an anti-friction roller 21 at its outer end. Thearm 23 is at the end of the v nector 19 and its contacts 2O and 21 between their different terminal connecting` positions.

Vith the parts in the positions shown in the drawings, the terminals and 11 are connected together by the connector. To shift the connector to the position in which connection is made between the terminals 10 and 15, the shaft 18 is rotated in a clockwise direction as seen in F ig. 2, the offset po-rtion of the shaft which carriesthe connector moving in a circular path about the axis of rotation of the shaft. Baring the first part of this rotation of the shaft 18, the contacts 2O andf21 are in engagement with and are heldrbetween the terminals 10 and 11 so thatthe connector is forced to rotate in aA counter-clockwisedirection, the roller 24 approaching the radial lby a togglefaction firmly into contact with the terminals 10 and 15, the roller 24 being withdrawn from the radial groove and moved into a position midway between the grooves nearest the terminals 12 and 13. This operation may be repeated to shift the connector to other positions connecting any two adja-k cent terminals. It is obvious that by rotating the shaft 18 in the opposite or counter-clockwise direction, the connector will be shifted in a clockwise direction oppositeto that just described; for instance, from the terminals 10 and 11 to the terminals 11 and 12.

The terminals 10 to 15 and contacts 2O and 21 are adapted to carry current continuously without injury but these contacts cannot be used to make or break the current without injury to both the contacts and terminals by arcing at the surfaces where the current is made or broken. To avoid this injury to the main contacts and terminals, an improved arrangement including auxiliary arcing contacts is provided. Any injury due to arcing takes place at these auxiliary contacts which are simple and inexpensive and which may be easily replaced whenever desirable.

An auxiliary connector, including the arcing contacts 27 connected together by a spring member 28, is secured to the outer end of an arm 29 projecting from a sleeve 30 surrounding the shaftc18. The sleeve 30 withits arm 29 and the auxiliary connector are arranged to rotate freely about one end of the shaft 18 beyond its offset portion so that the connector rotates in a circular path about the axis of rotation of the shaft 18. The main connector 19 carries a pin 31 which projects into a groove 32 in a plate secured to the arm 29. Thenever the main connector 19 moves to shift its main contacts 2O and 21 from one contact making position to another, the pin 31 will engage one 'side or the other of the groove 32 and shift the arm 29 with the auxiliary arcing contacts 27 between the same contact making positions. Each of the terminals 10 to 15 is tubular and has its inner side cut away opposite the arcing contacts 27. A small cylindrical iixed-arcing Contact l-l is secured within each of the tubular terminals 10 to 15 at its cut-away portion and the spring member 28 forces the movable arcing contacts 27 against these fixed contactsV 3/1 as shown in Figs. 3 and 4t. The pin 31 controls the auxiliary connector so that the auxiliary contacts and the 'spring member 28 always connect the same two terminals that are connected to gether by the main connector.

The main contacts 2O and 21 move from one contact making position to the next through a curved path which is convex toward the shaft 18 as already explained and the motion of the contacts at each end of this path has a large radial component toward or away from the shaft. The outer end of the groove 32 in the pl ate 33 is also enlarged so that there is some free space in this groove at each side of the pin 31. r.llhe main con acts 2O and 21 therefore leave the two main terminals with which they have been in contact before the pin 31 engages one side or the other of the groove 32 and therefore before the auxiliary arcing contacts start to move, the latter then carrying all the current and preventing any arcing at the main contacts as these are opened. The pin 31 is then drawn back into the narrower part of the groove 32 and engages one of its sides to shift the arcing contacts to the nextcontact making position. lt will be apparent that the arcing contacts will reach this next contact making position while the pin 31 is still in the narrower part of the groove 32 and that the main contacts will [inally be forced radially outward into the new position. in changing from one contact making position to the next, therefore, the circuit is always broken last and made first through the arcing contacts and no arcing can occur at the main contacts.

lWhat I claim as new and desire to secure by Letters Patent of the United States, is

l. A switch including a plurality of terminals, a main terminal connector, an auxiliary terminal connector, means for moving said main connector' from one terminal connecting position to another, and means for movingsaid auxiliary connector between the same terminal connecting positions during the motion of the main connector, whereby the main connector is protect-ed from arcing.

2. A switch including a plurality of terminals, a main terminal connector, an auxiliary terminal connector', means for moving said main connector from one terminal connecting position toanother, and means controlledvby said main connector moving means for moving said auxiliary connector between the same terminal connecting positions during the mo tion of the main connector, whereby the main connector is protected from arcing.

3. .fr switch including a shaft having an offset portion, a plurality of terminals spaced about said shaft, a main connector rotatable on the offset portion of the shaft, means for guiding the main connector from one termin ai co. necting position to another' as the shaft is rotated, an auxiliary connector rotatable on said shaft, and a pin and groove connection between said connectors.V

f1. A. switch including a shaft having an offset portiona plurality of terminals spaced about said shaft, a main connector rotatable e offset portion of the shaft, means -for ring the main connector from one terminal connecting position to another as the shaft is rotated, an auxiliary connector rotatable an said shaft, and a pin and groove connection between haid connectors, a portion of said groove being enlarged to provide lost motion between said connectors during part of their motion between terminal connecting positions.

ln witness whereof, 1 have hereunto set my hand this 30th day of Sept., 1929. Y

' LGUIS F. BLUME. 

